RE: Guest WLAN with VLAN (Dell PC 6248)

I would test connectivity on VLAN 15 by setting a static IP address and then trying to ping the default gateway address for VLAN 15 and any other devices on VLAN 15. If you have connectivity, then move on to the DHCP issue. If there is no connectivity, then continue to troubleshoot as a connectivity issue and not as a DHCP issue.

RE: Guest WLAN with VLAN (Dell PC 6248)

I setting a static IP address but i can't ping the default gateway address for VLAN 15.

Yes, the blue interface of the IPfire acting as a DHCP Server for VLAN 15.

If i plug the cable from the blue Interface directly in my laptop, i get a IP address and all works fine.But if i plug the cable in G36 and want to connect with the Guest WLAN, i didn't get a IP address.

RE: Guest WLAN with VLAN (Dell PC 6248)

On the 6248, are ports 15 and 36 in the up status? If you plug your laptop into a port on the 6248 that is set to be untagged for VLAN 15, can your laptop reach the gateway? This would further help identify if the issue is occurring on port 36 or port 22.